More on 20 mph streets

18 mph streets benefit all. They would also encourage more walking and bicycling. Instead of waiting for separate paths people would see fit to use the road. People are scared to use the streets for bicycling and walking because hostile traffic makes it preferable to be surrounded by steel. Presently over-designed streets would be simple and cheap to reuse; streets space can be allocated for other modes at 18mph. More importantly since slowing down traffic can be seen as increasing congestion, instead of congestion management we need congestion design.

Quote from Vanderbilt
We consistently get urban speeds wrong in the U.S. In Germany, the land where speed is supposedly worshipped, the speed-limit free sections of the autobahn are contrasted by a mandatory, heavily enforced 30 KPH (that’s 18 mph, folks) limit in residential areas.

Quote from Streetblog comments on the Times article
The case for traffic-calming and automated enforcement is already strong. This makes it even more airtight. Drivers are basically ignoring posted limits on roads designed to accommodate speeding. (Traffic author Tom Vanderbilt wrote a great post last month about the multi-pronged wrongheadedness of this approach to street design. Since drivers respond more to the threat of tickets than the inherent dangers of speeding, automated devices like red-light cams and speeding cams are essential to thoroughly deter this behavior.

Another quote-
The fact that this story was picked up by health reporters is an encouraging sidenote. Livable streets advocates will have powerful allies if public health authorities recognize unchecked speeding as the catastrophe that it is.